I want to covert my front to long arms and make the cross members and arms my self. I'd use square tube, where exactly on the lower arm do I mount the other though? It would be adjustable at one end of all arms. Other end will be just rubber or something.

unless someone is giving you material free, the cost is close to the same.

to give you a hint; 2"x.250 DOM tubing (what you need to do this) in materials for all arms came in close to 150$ (local price etc) you need to use .250 wall. nothing thinner. the upper
joints; i would go with currie JJs. two of these with the proper bungs/jam nuts was 150$ canadian. on US websites they are 44$ a piece. you need about three of them. you also need axle end regular bushings. those if i recall came close to 40$ a pop. so for all joints i needed to make these arms, i was at 400$ and 200$ in materials. NOT including the cross member, which is just going to be a whole bunch of fun for you to make. edit; i'm sure you can use some other cheap/crap bushings, but if you're using anything other than JJs and clevite type bushings, whats the point?

so like i said, unless someone is giving you the materials (at a loss to them?) and is wiling to put in a whole lot of time building this, its not worth it.

You can use 2x2 sq tube .25 thick for lowers and 1.5x1.5 sq tube .125 thick since its not going to be hitting rocks when I priced out that dom vs the 2x2 the DOM was 15 bucks a foot the 2x2 was 5 bucks a foot I do not recall anyone using the 1.5 sq tube for a front upper thoigh I have seen it on the rear upper.